Nestel P, Trumbo P
Arch Latinoam Nutr. 1999 Sep;49(3 Suppl 1):26S-33S.
That beta-carotene is the main source of vitamin A in fruits and vegetables has been known for many years. Many studies have been conducted to assess bioconversion of beta-carotene to vitamin A in animals. More recently, bioconversion studies using stable-isotopically labeled beta-carotene have been used to assess bioconversion in humans. The efficiency of the bioconversion of beta-carotene to vitamin A has been accepted to be six but this value may vary depending on vitamin A status and the amount of beta-carotene consumed. This paper reviews the human studies on purified beta-carotene supplements and/or consumption of fruits and vegetables conducted to ascertain whether beta-carotene can alter the vitamin A status of deficient populations. The conclusion is that data are lacking from well-designed studies to show that, with the possible exception of red palm oil, beta-carotene-rich foods are as effective as vitamin A supplements for eliminating vitamin A deficiency. Nevertheless, the data do show that beta-carotene-rich foods may be important for preventing vitamin A deficiency.
多年来人们一直知道，β-胡萝卜素是水果和蔬菜中维生素A的主要来源。已经开展了许多研究来评估动物体内β-胡萝卜素向维生素A的生物转化。最近，使用稳定同位素标记的β-胡萝卜素进行的生物转化研究已被用于评估人体中的生物转化。β-胡萝卜素向维生素A的生物转化效率公认为是6，但该值可能因维生素A状态和β-胡萝卜素摄入量的不同而有所变化。本文综述了为确定β-胡萝卜素是否能改变缺乏维生素A人群的维生素A状态而进行的关于纯化β-胡萝卜素补充剂和/或食用水果和蔬菜的人体研究。结论是，缺乏精心设计的研究数据表明，除了红棕榈油可能是个例外，富含β-胡萝卜素的食物在消除维生素A缺乏方面与维生素A补充剂一样有效。然而，数据确实表明，富含β-胡萝卜素的食物对于预防维生素A缺乏可能很重要。
